FMU Question.
04-23-2005, 04:23 AM
#1
1.0 BAR
Thread Starter
Join Date: Apr 2005
Posts: 375
FMU Question.
Well got the Turbo runing fine.
As long as there is gas in the carb bowl she is shreding up her rubbers.
But then the float bowl goes dry and she stalls.
Yeah I know you guys hate FMUs and all that.
But this is a carbed setup so no other option.
Keeping that in mind.
What would be my best FMU the market seems to be flooded with total crap. Its hard to make a call.
As long as there is gas in the carb bowl she is shreding up her rubbers.
But then the float bowl goes dry and she stalls.
Yeah I know you guys hate FMUs and all that.
But this is a carbed setup so no other option.
Keeping that in mind.
What would be my best FMU the market seems to be flooded with total crap. Its hard to make a call.
04-24-2005, 02:50 AM
#6
1.0 BAR
Thread Starter
Join Date: Apr 2005
Posts: 375
Re: FMU Question.
Thanks CRX2fast that was the kind of info I was looking for.
Guys on a carbed setup its obvious your going to need a fuel pump with a higer PSI rating than the boost your runing or the car will ---- out. Every time you hit boost.
My present setup.
A new fuel pump in the tank from an EFI car which makes 65 PSI.
This is connected to my home built FMU which is nothing but a modifed fuel regulator found at the end of fuel rail. Its cut up and setup so that manifold presure is connected to a nipple on top of it. THe spring is replaced with a softer spring. It has a new return line laid back to the tank.
How its suposed to work is under no boost it will supply 5 PSI to the carb. THe rest of the fuel is returned to the tank.
As it sees boost it will press down on the spring releasing more fuel flow from the pump. Towards the carb. The carb uses how much fuel it needs and the excess fuel is returned back to the tank via the fuel return line.
Yes I know it sounds stupid but we do have two fuel return lines. I could have just used the existing fuel return line.
TOday need to strip down the setup and chk if its the fuel pump or my FMU thats acting up. We have another car with the same setup runing fine.
If its my FMU may as well just get something that works out of the box.
We are adding our own ECU which is a wide band sensor runing closed loop to a single injector under the carb. So far Ive only finished the WB o2 circuit. Now just need to add injecotr and ignition circuit. If I can find a knock sensor at the junk yard we will do a circuit for that too. Ignition is allready working. O2 done. So only the injecotr setup left. Yes I know about megasquirt but I want to do our own Getho setup. Copying some other guys design isnt as much fun some how.
So man Ill hit egay and chk for Vortech.
Guys on a carbed setup its obvious your going to need a fuel pump with a higer PSI rating than the boost your runing or the car will ---- out. Every time you hit boost.
My present setup.
A new fuel pump in the tank from an EFI car which makes 65 PSI.
This is connected to my home built FMU which is nothing but a modifed fuel regulator found at the end of fuel rail. Its cut up and setup so that manifold presure is connected to a nipple on top of it. THe spring is replaced with a softer spring. It has a new return line laid back to the tank.
How its suposed to work is under no boost it will supply 5 PSI to the carb. THe rest of the fuel is returned to the tank.
As it sees boost it will press down on the spring releasing more fuel flow from the pump. Towards the carb. The carb uses how much fuel it needs and the excess fuel is returned back to the tank via the fuel return line.
Yes I know it sounds stupid but we do have two fuel return lines. I could have just used the existing fuel return line.
TOday need to strip down the setup and chk if its the fuel pump or my FMU thats acting up. We have another car with the same setup runing fine.
If its my FMU may as well just get something that works out of the box.
We are adding our own ECU which is a wide band sensor runing closed loop to a single injector under the carb. So far Ive only finished the WB o2 circuit. Now just need to add injecotr and ignition circuit. If I can find a knock sensor at the junk yard we will do a circuit for that too. Ignition is allready working. O2 done. So only the injecotr setup left. Yes I know about megasquirt but I want to do our own Getho setup. Copying some other guys design isnt as much fun some how.
So man Ill hit egay and chk for Vortech.
04-25-2005, 02:38 AM
#10
3.0 BAR
Join Date: Apr 2003
Posts: 2,260
Re: FMU Question.
He seems to have it "worked out", however, I would like to see how well the floats work under that amount of fuel pressure.
Especially with the FMU pushing out between 8 - 12 psi on top of that per psi of boost... will be interesting to see how this works out.
Especially with the FMU pushing out between 8 - 12 psi on top of that per psi of boost... will be interesting to see how this works out.
